title: Versatile N2S2 nickel-dithiolates as mono- and bridging bidentate, S-donor ligands to gold(I).
abstract: Development of square planar cis-dithiolate nickel complexes as metallo S-donor ligands focuses on the synthesis and structures of gold(I) heterometallic clusters derived from assemblage with three NiN2S2 complexes: Ni(bme-daco), Ni(bme-dach) and Ni(ema)(2-) (bme-daco = (bismercaptoethanediazacyclooctane); bme-dach = bismercaptoethanediazacycloheptane; and ema = N,N'-ethylenebis-2-mercaptoacetamide). With Ph3PAuCl as the gold source, examples of simple S-aurolation retaining the PPh3 on Au(+) were obtained for [{Ni(bme-daco)}AuPPh3](+)Cl(-) and [{Ni(ema)}2Au4(PPh3)4], where the latter complex demonstrated unsupported aurophilic interactions between [{Ni(ema)}Au2(PPh3)2] units in its X-ray crystal structure (Au-Au = 3.054 and 3.127 Å). Three compounds containing fully-supported digold units with Au-Au distances in the aurophilic range of 3.11 to 3.13 Å were found as stair-step structures in which planar NiN2S2 step treads are connected by planar S2Au2S2 risers at ca. 90°: [{Ni(bme-daco)}2Au2](2+)(Cl(-))2; [{Ni(bme-dach)}2Au2](2+)(Cl(-))2; and (Et4N(+))2[{Ni(ema)}2Au2](2-). Electrochemical data from cyclic voltammograms demonstrated a positive shift in Ni(II/I) couples for the [{NiN2S2}xAuy] complexes as compared to the NiN2S2 precursors and a ca. 700 mV decrease in communication between multiple NiN2S2 units as compared to [{NiN2S2}2Ni](2+) analogues in slant chair conformation. The analogy between NiN2S2 metallodithiolate ligands and diphosphine ligands holds here as in other examples of inorganic and organometallic complexes.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, TX 77843, USA. marcetta@chem.tamu.edu.
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Pinder
authors.forename: Steven K
authors.initials: SK
authors.lastname: Montalvo
authors.forename: Allen M
authors.initials: AM
authors.lastname: Lunsford
authors.forename: Chung-Hung
authors.initials: CH
authors.lastname: Hsieh
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Reibenspies
authors.forename: Marcetta Y
authors.initials: MY
authors.lastname: Darensbourg
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D013438:Sulfhydryl Compounds; D013455:Sulfur; D006046:Gold; D009532:Nickel